virtio_net: enhance wake/stop tx queue statistics accounting

This patch refines and strengthens the statistics collection of TX queue
wake/stop events introduced by commit c39add9b2423 ("virtio_net: Add TX
stopped and wake counters").

Previously, the driver only recorded partial wake/stop statistics
for TX queues. Some wake events triggered by 'skb_xmit_done()' or resume
operations were not counted, which made the per-queue metrics incomplete.

Signed-off-by: Liming Wu <liming.wu@jaguarmicro.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20251120015320.1418-1-liming.wu@jaguarmicro.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index cfa006b88688759785010672dba70b5185c939be..b0947e15895f4199d82f2a1ea66e4ae7f7211dec 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -775,10 +775,26 @@ static bool virtqueue_napi_complete(struct napi_struct *napi,
        return false;
 }
 
+static void virtnet_tx_wake_queue(struct virtnet_info *vi,
+                               struct send_queue *sq)
+{
+       unsigned int index = vq2txq(sq->vq);
+       struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index);
+
+       if (netif_tx_queue_stopped(txq)) {
+               u64_stats_update_begin(&sq->stats.syncp);
+               u64_stats_inc(&sq->stats.wake);
+               u64_stats_update_end(&sq->stats.syncp);
+               netif_tx_wake_queue(txq);
+       }
+}
+
 static void skb_xmit_done(struct virtqueue *vq)
 {
        struct virtnet_info *vi = vq->vdev->priv;
-       struct napi_struct *napi = &vi->sq[vq2txq(vq)].napi;
+       unsigned int index = vq2txq(vq);
+       struct send_queue *sq = &vi->sq[index];
+       struct napi_struct *napi = &sq->napi;
 
        /* Suppress further interrupts. */
        virtqueue_disable_cb(vq);
@@ -786,8 +802,7 @@ static void skb_xmit_done(struct virtqueue *vq)
        if (napi->weight)
                virtqueue_napi_schedule(napi, vq);
        else
-               /* We were probably waiting for more output buffers. */
-               netif_wake_subqueue(vi->dev, vq2txq(vq));
+               virtnet_tx_wake_queue(vi, sq);
 }
 
 #define MRG_CTX_HEADER_SHIFT 22
@@ -3080,13 +3095,8 @@ static void virtnet_poll_cleantx(struct receive_queue *rq, int budget)
                        free_old_xmit(sq, txq, !!budget);
                } while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
 
-               if (sq->vq->num_free >= MAX_SKB_FRAGS + 2 &&
-                   netif_tx_queue_stopped(txq)) {
-                       u64_stats_update_begin(&sq->stats.syncp);
-                       u64_stats_inc(&sq->stats.wake);
-                       u64_stats_update_end(&sq->stats.syncp);
-                       netif_tx_wake_queue(txq);
-               }
+               if (sq->vq->num_free >= MAX_SKB_FRAGS + 2)
+                       virtnet_tx_wake_queue(vi, sq);
 
                __netif_tx_unlock(txq);
        }
@@ -3276,13 +3286,8 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
        else
                free_old_xmit(sq, txq, !!budget);
 
-       if (sq->vq->num_free >= MAX_SKB_FRAGS + 2 &&
-           netif_tx_queue_stopped(txq)) {
-               u64_stats_update_begin(&sq->stats.syncp);
-               u64_stats_inc(&sq->stats.wake);
-               u64_stats_update_end(&sq->stats.syncp);
-               netif_tx_wake_queue(txq);
-       }
+       if (sq->vq->num_free >= MAX_SKB_FRAGS + 2)
+               virtnet_tx_wake_queue(vi, sq);
 
        if (xsk_done >= budget) {
                __netif_tx_unlock(txq);
@@ -3537,6 +3542,9 @@ static void virtnet_tx_pause(struct virtnet_info *vi, struct send_queue *sq)
 
        /* Prevent the upper layer from trying to send packets. */
        netif_stop_subqueue(vi->dev, qindex);
+       u64_stats_update_begin(&sq->stats.syncp);
+       u64_stats_inc(&sq->stats.stop);
+       u64_stats_update_end(&sq->stats.syncp);
 
        __netif_tx_unlock_bh(txq);
 }
@@ -3553,7 +3561,7 @@ static void virtnet_tx_resume(struct virtnet_info *vi, struct send_queue *sq)
 
        __netif_tx_lock_bh(txq);
        sq->reset = false;
-       netif_tx_wake_queue(txq);
+       virtnet_tx_wake_queue(vi, sq);
        __netif_tx_unlock_bh(txq);
 
        if (running)